Torsional vibration dampener



w. L... FISCHER TORS IONAL VIBRATION DAMPENER Filed May 9, 1940 ZSheets-Sheet 1 FIG-4.

' INVENTOR.

W/LL/AM L. F/SCHEI? ATTORNEY.

y 3943 l v w. l... FlSQ ER 2 1?,98 3- TORSIQNAL VIBRATILON" DAMPENER FiledMay e, 1940 r 2 s ets-sheet 2 INVENTOR.

W/LL/AM L. F/SCHE ATTORNEY.

this invention is to obtain Fig. 3is a section online 3-3 Patented M 7 m-gsot;gsmgs PATENT" fjorrics I "IVORSIONA'L VIBRATION D AMPENER w i11 am 11. Fisc er, rm aaeipmara. 1940, Serial No. 334,223] 1 AppiicationMay 9.

' "i (Granted under theac t of'March a, 1883, as

amended April so. 1928;; 370 '0. G. my l I This invention relatesto a torsional vibration dampener' and has for an object-toiprovide a torsionalv vibration dampener of comparatively;

simple construction and having the minimum of moving parts and --upkeep.. A further object of;

this invention is to provide animprovement in the liquid torsional vibration dampeners shown in applicantfs'prior Patent No. 2,180,35lof No-. I vember'2ljl939, in utilizing -a solid resonance pendulum weight rather than. the liquid pendulum weight therein disclosed.

Another object of this invention is to provide an improved torsional vibration dampener;utilizinglless movable parts and less fixed parts than used, for instance, in United States Patents Nos.

which show anow well-known torsional vibration dampener 2103.643 and 2,029,796, bothof designed on the principle ofthe resonance pendulum.

'- --'Ihe"'fo1lowing invention, however, deals with g a peculiar design of' such a dampener, which for certain practical applications, offers considerable advantages, as will be shown. Especially'in cases where'little room is availablefor a dampener in the counterweight of acrankshaft andmore so, if such a dampener has to be tuned to a low harmonic order, for example; to :1 /2 vibrations per crankshaft revolution, conventional designs lead to complicated and highly stressed structures and to very small'roller masses. .The primeqobjectof a large pendulum roller mass and a simple and reliablejconstruction for s ch cases as cited before. Other. objects. of this inventionwill become description and from the drawings; in'which:

Fig. l isa partly sectional front view on'line l--| of -'Fig.2, of. the dampener: as applied to a crankcheek of a crankshaft;

Fig. 2 is aside view of-Fig. 1; r

of Fig. 1; Fig. 4 is a view similar to Fig.

form utilizing tworollers; Fig. 5 is a side view of Fig. 4;.,

ion line 8-4 of His aninsert r tersunk rivets I and V I ciding' with the edge of thefcrankcheek l4.

about the axis of ammon a. immanent I is provided with a count M which insteadiof beingsolid. as customary, thin parallel flanges 2,

has been formed int o two integraiwith the crankshaft .j, Secured between the outer edgeslli of the flanges 3 held in position by bolts or counhaving an outer edge coin- An inner edgeconsisting oil a"'concavely ground raceway 4 is formed onthe insert 3 andpi'ovides fora cylindrical. roller- 5,.th'is .rcller5 being preferably made'of a tung,-, sttn alloy rather than steel so as to have the a concave guiding surface maximum available mass within the limits provided by the availabledimensions.

The center of curvature of the raceway l is located at ll eccentric to the axisof rotation l1 and is such that the openings I 0 left by the cavity formed by the insert '3 and flanges 2'is considerably less than the diameter of the roller 5; The roller 5 'hits the;cavityjwa1ls= at the position 9 a just before its peripheral edge'would coincide of the flangesig The open- 1 .fings. I!) provide room for the admission of air with the side edges and oil'mist;.whi1e the crankshaft l 'isrotati ng,

, the oil level being maintained at the position 8 during rotation of the crankshaft through the obvious from the following v Fig. 6 is a partly sectional front view of the dampener utilizing a plurality of rollers as applied to a disk or flywheel mountedon 1a crankshaft;

and

Fig. '7 is a partly sectional side view of Fig. .6. In the various forms of reference numbers have been used where the same structure performing the same function is disclosed.

There is shown at l the crankshaft of an in -line engine provided with a plurality of crankisshown, rotatable pins 12, only one of which thedrawingsthe same presence of oildra'in hole the flanges 2 adjacent the ."This roller; 5. has

\iffthe raceway 4 which is axisof rotationl3.

2 and isfreefto oscillate under theL'action-of centrifugal, vibrationa'nd inertia forces; which occur when the crankshaft is running under loadan'dsubmitted .to torsional design as shown inFlg. 1, theroller canjtravel approximately degrees. to either side from its neutral position before it hits the cavity wall's, as

flAccording to the"accepted indicated by item 9. V .hiory of the pendulum dampener (see forexample}. P. den Hartog,Tuned Pendulurns as; Torsional Vibration Eliminators, MacMillan'Cd, 1838', age 25); the maximum damping torque reducible with such a roller is reached "at around It istherefore (with due iod eg rees to one side.

i cgard to the fact that the roller will overrun't'ne maximum torque position somewhat, but should not hit thestop) possible to reduce the raceway are considerably, and in doing so R becomes small and for a given low harmonic orderH the I distance L becomes also small as per basicformula L=R:H=, and a large size roller is the result.

rbalancing. c'rankcheek 2 of crankcheek s 6 extending through 1 point on the curvature furthermost from the a' small side iclearance with respect to thefianges vibrations'of the 1 /2 order for example. Inthe.

. bushing would lead to modifications.

the crankshaft Purposes without the of the crankcheek a v 1 cylirslenwhose main For design conditions as illustrated by Figs. 1 and 2, the use of a conventional full circle racewa a roller diameter ofabout and thus to a mass much too small for praca tical use. 7

While Figs. 1 and 2 show only one crank with one roller dampener, it is obvious that the new way of housing a roller dampener in ,a crankshaft counterweight could be used in various For example, two rollers could be housed side by side in one counterweight (see Figs. 4 and 5), housed in a disk or flywheel rigidly attached to (see Figs. 6 and 7). I Obviously such rollers could either all be tuned to the same or to different harmonic orders; For example, a six throw crankshaft having six counterweights could have one or mor rollers in each counterweight and of various tunings, thus'being pro-v tected against vibrations from various'harmonics.

Other modifications and changes in the proportionsand arrangements of the parts may be madeby those skilled in'the art scope of what is hereinafter claimed. v

The invention described herein may bemanufacturedand/or used by orffor the Government of the :United States of America for governmental payment of any royalties thereonortherefonj Y Having thusset'forth and disclosed the nature of this invention, what is claimed is:

11. In' combination direction substantially opposite to the crankpin and in 'a'plane p'erpendicular'to the axis-of rota-' 7 direction substantially opposite to the crankpin and in a plane perpendicular to the axis of rotation of said crankshaft and defining a radial slot therebetween,- the outer surfaces of the flanges being in the same planes as the outer surfaces rigid insert held rigidly within said radial'slot between said two flanges, a concave raceway are extendin longitudinally on said insert, and acylindrical wafeir roller free to move along the concavity on said raceway are be-- or a number of rollers could be with a crankshaft, two, par allel flanges protruding from a crankcheek in aof rotation of said crankshaft, but oifsetfromlt in a direction opposite to thecrankpln, the path of thegeneratrix of the lateral surface of the clrcular cylinder intersecting the crankshaft.

4;. In combination withacrankshaft, two par-- allel flanges protruding froma crankcheek in a direction substantially opposite to thje crankpin and in a plane perpendicular to the axis of rotation of said crankshaft and defining a radial slot therebetween, the outer surfaces of the flanges being in the same planes as the outer surfaces of the crankcheek a rigid insert held rigidly within said radialslot between said two flanges, a concave raceway are extending longitudinally on said insert, the distance between the centers of the crankshaft and the arc on said insert being less than the wafer roller free to movealon'g the concavity on I said raceway arc between'f'said two flanges, said I without departing from the nature of the invention, within the beingin the same tween said twc'flanges. said two flanges being integral with the crankshaft structure. 3. .In'combination with a crankshaft, two parallel flanges protruding from a crankcheek in'a directionvsubstantially opposite to the crankpin and in a plane perpendicular to the axis of rotation of said crankshaft and defining a radiol slot therebetween; the outer surfaces of the flanges being inthe same planes as the outer surfaces of the crankcheek a rigid insert held rigidly withv ofthe crankcheek a rigid siderations will permit to make allel flanges protruding from therebetween, the

said raceway arc rollerhavinga diameter greater than the radiusraceway extending overnot more than degrees. 1

5. In combination with a: crankshaft, two par- -allel flanges protruding from a crankcreek in a direction substantially opposite to the cranlrpin and in a plane perpendicular to;the axis of rota-- tion of said crankshaft and'defining a radial slot; therebetween, the outer surfaces. of theflanges planes as the outer surfaces of the crankcheek a rigid insert held rigidlyjwithin said radial slot between said, two flanges, aconcave raceway are extending longitudinally on said in sert, the distance between the centers roof the crankshaft and the arc on said insert'being less thanthe sumcf their radiLand a cylindrical wafer roller free to movealong the concavity on said raceway are between said two flanges, said cylindrical roller-being free to ro1l,to slide,-or

to roll'and slide over said raceway-with little friction under the action f centrifugal,v vibration and inertia forces. s 6.- In combination with a crankshaft, two parallel flanges protruding from a crankcheek in a direction substantially opposite to the'crankpin and ma plane perpendicular to the axis of rotation of said crankshaft and defining a radial slot therebetween, the outer surfaces :oftheflfianges being in the same" planes. as the outer surfaces insert held rigidly within said radial slot between said two flanges, a concave raceway are extending longitudinally on said insert, and a cylindrical wafer roller free to move along-the concavity on said raceway are between said'two flanges, said two flanges being parallel to each other and as thin as stress con them. 7. In combination with a crankshaft, two par- 3, crankcheek in a direction substantially opposite tothe' crankpin and in a'plane perpendicular to the axisof rotation of said crankshaft and defining a radial slot outer surfaces of ,the flanges planes as the outer surfaces rigid insert held rigidly withbetween" said two flanges, a

being in'the same of the crankcheek a in said radial slot concave raceway are extendin longitudinally on said'insert, the distance between the centers of less thanthe sum of wafer rollerfree to'move along the concavity on between said two flanges, said of said are. H l

. r L. FISCHER.

sum of their-radii. and a cylindrical 

